GRE Big Book is one highly recommended book for GRE preparation. This book is a compilation of 27 real test papers along with answer keys. ETS had released this book and that makes GRE Big Book the official document for GRE tests practice. There are no other tests in this book prepared solely for the purpose of practice, nor is there any explanation of concepts and strategies or list of formulae. GRE Big Book is just a collection of genuine test papers. This book is not printed any more.
The most significant feature of GRE Big Book is that it was released by ETS. ETS itself conducts and administers the GRE and consequently the GRE Big Book is the most reliable source for preparation. It does not contain tests which were prepared for mere practice but those which were actually administered in the GRE. There is no other such book available which contains the original tests. With such a large number of actual questions available in the GRE Big Book.
